Multilayer micro fluidic devices comprising at least one layer with fluidic paths or channels or fluidic structures that achieve two-dimensional (2D) hydrodynamic focusing (in plane directions) are known. These multilayer devices, or the individual layers, are produced by means of known techniques such as, for example, etching, injection moulding, punching, and cutting.
For example, WO 01/25137 discloses the production of modular 3-dimensional (3D) micro fluidic devices using a plurality of layers, most of which are produced and processed by etching processes known e.g. from photolithography. Within the disclosed devices fluidic channels are arranged in a plurality of layers, the channels being interconnected between the various layers thus creating a 3D fluidic network.
WO 99/19717 and U.S. Pat. No. 6,827,906 both disclose the production of 3D micro fluidic devices containing microstructure arrays. The transport of fluids through micro channels is achieved by means of electro osmotic flow or by means of electrophoresis. The micro fluidic devices are multilayer arrays, each layer being formed by a laminate continuously drawn from a roll and passed trough a process step for producing openings, reservoirs, flow channels, and the like.
Further, EP 1 542 010 describes an analytical chip unit comprising various layers, through which a flow channel is extending. Through the flow channel, whose section is in closed shape, a fluid sample is made to flow for carrying out analyses regarding the fluid sample based on interaction between a predetermined substance and a specific substance, which is placed facing said flow channel. The chip further has a projection member attached to said flow channel. It is concluded that with the arrangement according to EP 1 542 010 it becomes possible to analyse the fluid sample efficiently with high precision.
The disadvantage of known 3D microstructures and the processes for producing these 3D microstructures is that they can only by obtained by using various layers of 2D substrates or by complex processes such as several etching processes. In other words, the production costs for the known 3D microstructures are quite substantial.